# Is HBr a strong acid?

Jun 5, 2018

Yes!

#### Explanation:

In the Bronsted-Lowry definition, an acid is anything which donates ${H}^{+}$ ions in an aqueous solution.

$H B r$ would be considered an acid, because it does dissociate in aqueous solutions in the following dissociation reaction:

$H B r \left(g\right) r i g h t \le f t h a r p \infty n s {H}^{+} \left(a q\right) + B {r}^{-} \left(a q\right)$

Now, a strong acid is an acid which almost completely dissociates in aqueous solutions.

$H B r$ fulfils this, because it very readily dissociates—here's why.

$H B r$ is a hydrohalic acid, or an acid with the formula $H X$ where $X$ is a halogen.
In all hydrohalic acids except for $H F$, the bond between $H$ and $X$ is very weak because halogens tend to:

• have a high number of energy levels, increasing the size of the halogen. This decreases attraction between $H$ and $X$.
• Be very electronegative, causing the $H - X$ bond to be very polar.

These two factors cause hydrogen to be very easily "snapped off" of $H X$, causing it to dissociate into ${H}^{+}$ and ${X}^{-}$.

This is also true for $H B r$—because bromine is so electronegative and large, hydrogen will very easily dissociate from $H B r$, causing $H B r$ to readily dissociate into ${H}^{+}$ and $B {r}^{-}$.

Dissociation happens so readily that we can say $H B r$ almost completely dissociates, fulfilling the criteria for a strong acid.